Portable electronic devices often are enclosed within small form factor housings to make carrying and/or wearing the devices more convenient. Unfortunately, this makes the efficient utilization of space available within the housings of great importance. Some housings include various protrusions and/or recesses that make the device more comfortable to wear or enhance the overall function of a particular sensor. These irregularly shaped protrusions and recesses can result in empty space within the housings that goes unutilized.